[tainted1899]

Hi everyone! I have a few queries regarding boiling point elevation and colligative properties that i hope you can help me understand...

why is it that colligative properties only apply to dilute solutions?

also, what kinds of solutions and solvents can be used for the experiment on boiling point elevation?

lastly, what are the advantages of this experiment compared to other methods?

I would really appreciate your help as I've tried searching for the answers to these questions for a long time but didnt manage to find out anything substantial...

thanks alot!  

[Hunt]

why is it that colligative properties only apply to dilute solutions?

You can apply them to concentrated solutions, but you'll never get precise results ( for electrolyte solutions, that is ). It is because the higher concentration of a solution, the greater the probability of ion pairing. Hence, i_theo > i_exp. Incase of dilute solutions, the probability of ion pairing is minimal, i_theo ? i_exp.

also, what kinds of solutions and solvents can be used for the experiment on boiling point elevation?

 
I'm not sure if there is any restriction on types of solvents/solutes when it comes to ideal solutions.

lastly, what are the advantages of this experiment compared to other methods?

 
If you wish to determine the molar mass, then using osmotic pressure gives much more accurate values in most cases, especially when the change in temp is very low, than those from freezing pt depression or boiling pt elevation. It is because the change in height ( e.g mercury ) , no matter how small, can be detected accurately but a very small change in temp cannot.

If you wish to determine the change in boiling pt temp of a rxn ( e.g adding a solute to water ) , then this experiment could be useful for non-electrolyte solutions. For strong electrolytes, the solution must be dilute and the precision of ?T depends on the value i. For weak electrolytes, however, this is not probable.